Install all packages from wheels during tests
Install all packages from wheels during tests

This should help us catch missing wheels on supported platforms, see #629.
(No macOS wheels for dnaio available.)

This adds option `--only-binary :all:` to the `pip install` command.
This also covers all the test dependencies (pytest etc.), and only listing
non-test requirements would be more accurate, but the test requirements are
all available as wheels, so it should be fine.

marcelm/cutadapt